title: Thyroid autoimmunity in Type 1 diabetes: systematic review and meta-analysis.
abstract: OBJECTIVE
  To review the incidence and evidence for screening for thyroid autoimmunity and thyroid dysfunction in Type 1 diabetes.
  
  
  METHODS
  Systematic review and meta-analysis. Inclusion criteria were prospective cohort studies screening for thyroid autoimmunity and/or dysfunction (defined as an abnormal thyroid-stimulating hormone level) in Type 1 diabetes. Exclusion criteria included pregnancy and thyroid dysfunction before diabetes onset. Outcomes examined were: incidence of thyroid autoimmunity and/or dysfunction; association between thyroid autoimmunity and dysfunction; and cost-effectiveness. Data sources were MEDLINE, EMBASE, the Cochrane Library, manual searching and contact with authors, with limitations to English language and human studies. Meta-analysis was performed using random effects models.
  
  
  RESULTS
  We identified 14 eligible studies, involving 2972 young people and 789 adults with Type 1 diabetes. Follow-up ranged from 1-18 years. None of the studies were of good methodological quality (Newcastle Ottowa Scale score > 7). The incidence of thyroid dysfunction (11 studies) ranged from 27 (95% CI 15-45) to 246 (95% CI 118-453) per 10 000 patient-years and thyroid autoimmunity (four studies) from 13 (95% CI 0.3-71) to 326 (95% CI 194-510). The risk of thyroid dysfunction was higher in those with thyroid autoimmunity: summary risk ratio 25 (95% CI 9-71) and was higher in children (49, 95% CI 16-150) compared with adults (7, 95% CI 3-13). No studies examined cost-effectiveness of screening.
  
  
  CONCLUSIONS
  There is a markedly increased risk of thyroid dysfunction in people with Type 1 diabetes and thyroid autoimmunity. The optimal method or frequency of screening could not be determined from available data. Future studies should examine whether screening improves clinical outcomes in this population.
authors.affiliation: School of Women's and Children's Health, University of New South Wales, Sydney, NSW, Australia.
authors.forename: C B
authors.initials: CB
authors.lastname: Shun
authors.forename: K C
authors.initials: KC
authors.lastname: Donaghue
authors.forename: H
authors.initials: H
authors.lastname: Phelan
authors.forename: S M
authors.initials: SM
authors.lastname: Twigg
authors.forename: M E
authors.initials: ME
authors.lastname: Craig
mesh_terms: D000328:Adult; D015551:Autoimmunity; D003922:Diabetes Mellitus, Type 1 / Q000150:complications* / Q000453:epidemiology / Q000276:immunology / Q000503:physiopathology; D005260:Female; D006801:Humans; D015994:Incidence; D011247:Pregnancy; D013959:Thyroid Diseases / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D013961:Thyroid Gland / Q000276:immunology / Q000503:physiopathology; D013967:Thyroiditis, Autoimmune / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology